Rape Victims Left in Dark on HIV Threat : Health: Law shields the disclosure of a suspect's status. One man is suspected of raping 15 women, but only four have learned if he carries the AIDS virus.

Johnson, a resident of Lake View Terrace, is a convicted criminal with a long record and a list of aliases, including Monnette C. Alford Johnson. Police say he prowled Valley neighborhoods and raped his victims at knifepoint after entering their houses and apartments through unlocked doors and windows.

He is charged with 28 counts of rape, burglary, robbery and other crimes for a series of attacks police say he committed from August, 1991, until he was arrested in January, 1992.

At his trial, scheduled to begin today in Van Nuys Superior Court, prosecutors say they will try to convict him on the basis of witness testimony, DNA testing and other evidence. Property stolen from some victims was found at his apartment, police say.

Johnson's lawyer, M. David Houchin, has said in court documents that such DNA testing is faulty. Johnson has pleaded not guilty to all charges. He was released from parole in July, 1991, after serving nearly a year for an extortion conviction. Authorities allege that the rapes started soon afterward.